For celebrities the advent of the selfie was a digital dream come true.

It meant THEY could control their own images, tweeting directly to their fans, plugging their latest movies or albums and endorsing lucrative brands.

But that was five years ago, before smartphones with front-facing cameras became a must for a social media generation obsessed with fame.

Suddenly fans were no longer content to just retweet or share snaps of their favourite stars. They wanted to be in there with them.

They could even buy “selfie sticks” – 3ft extendable rods with a cradle for a phone, allowing bigger group shots or more background.

Perfect for getting all of One Direction in a single shot.

Then it got competitive – who could get the most pics of famous people to post on Facebook, Instagram or Twitter? And that’s when the selfie turned on the celebs.

Now actors, musicians and sports stars feel they are under attack in a constant photographic bombardment.

Forget the likes of Justin Bieber and Miley Cyrus, who have grown up on Twitter and Instagram. Or Kim Kardashian and Kelly Brook , who have made the belfie (bum selfie) their own.

(Image: iamkb, kimkardashian/instagram)

It’s the stars who still want a private life who are most aware of the scourge. Like much-loved TV star Paul O’Grady, who wants to make it clear that he’s not “a whingeing old fart” but has simply noticed a massive change in public behaviour.

“The whole selfie thing is just ridiculous,” he says. “I don’t mind talking to anyone and it’s lovely when fans want a natter about your show.

"But these days instead of having a conversation, it’s ‘Can I have a photo?’ Click, click, click. That’s if they bother to ask.

“If you’re on telly you have to expect people will want to talk to you or take a picture. It’s the price of fame. But don’t just come charging at me with your iPhone or iPad in your hand and start clicking. ASK ME!

“The worst ones go, ‘Oh, you’re thingy off the telly!’ Thingy?? They don’t even know who I am yet they want a picture! It’s a new form of collecting. Years ago you had trainspotters and stamp collectors. Now they collect photos of celebs.

“But I’ve got friends in the business who rarely go out now because it’s too much hassle. They say, ‘It’ll pass – it’s a fad.’ But it’s not a fad. It’s only going to get worse."

(Image: Getty)

He continues: “Cilla Black and I went to an awards dinner recently and neither of us ate or drank a thing because we stood and posed for photos all night. You can’t even go to the lav – they follow you in to get a photo.

“Reality shows have made it worse. Those people live their lives on screen. So the public think we’re all like that and love being photographed.

“It’s a pain in the neck. I’ve missed trains because of people stopping me on the platform for selfies. But it’s easier to say yes than be confrontational. I don’t want people saying, ‘He’s a right a***hole.’

“I’ve got three choices – stay in with a towel over my head, get off the telly and find another job, or get on with it. So I smile and move on. But I’d hate to be a really big international star. It must be awful.”

The part-time New York barmaid spends up to 12 hours a day hunting her targets.

She has snaps with stars including Lady Gaga, Matt Damon, Brad Pitt and Johnny Depp and admits: “I’m completely obsessed. It’s the most important thing in my life.”

This desperate desire to be photographed with the famous won Vanessa her own 15 minutes of fame when she featured in an episode of the TLC show My Crazy Obsession.

Vanessa says: “Celebrities are everywhere. I’ve found them just walking down the street or even at the train station. You have to keep your eyes open.

“A lot of people find what I do a bit strange. But some live their lives in their own little jars and don’t understand any­thing outside of it.”

Lady Gaga and Cher are Vanessa’s favourites because they always stop and pose. Bruce Willis, however, is a diehard selfie-dodger.

(Image: REUTERS)

But these days even A-listers have to think twice about saying no. In June Leonardo DiCaprio was out with pals in a New York nightclub when a drunken woman “fell” into his lap gushing: “It’s my birthday – I want a picture with Jack from Titanic!”

Leo wished her happy birthday but politely said “Sorry, not tonight.”

Showbiz websites were quickly reporting it as: “Leonardo DiCaprio refuses to take selfie with fan for birthday!” So why has social media changed our opinions and expectations of the stars?

Psychologist Linda Papadopoulos says: “We have a greater sense of ownership over celebrities. We feel we have a relationship with them.

“In the past you read about celebs in the papers but now they are all over Twitter. We know the type of cereals they eat, where they are at any moment... sometimes they even tweet us back so our sense of entitlement increases.

“We are pseudo celebrities ourselves. Using social media is like releasing press releases on our lives: ‘Look at the trip that I went on, look at the handbag I bought.’